Vacuum check air valve for vapor heating systems



July 4, 1933. w K, 5|MP50N 1,916,695

VACUUM CHECK AIR VALVE F'OR VAPOR HEATING SYSTEMS Filed Oct. 9, 1930 return line when the pressure in the return y .Y l

' parts adjacent thereto of the steam main and Patented July 4, 1933 UNITED isTAUS:sd PATENT OFFICE wrilLIAivrv K. SIMPSON, orj` WATERBURY, CONNECTICUT, ASSIGNOR 'To HOFFMAN SPECIALTY COMPANY, or `wATiiniaUnY, V-GONNEoTIoUT', A CORPORATION OF,

ILLINOIS VACUUM CHECK AIR vAmL'i non VAPOR nEATING SYSTEMS Application filedk October 9, 1930. Serial No. 487,439,

v yThe present invention relates to valves 'adapted to be applied to the return lines of Vlow pressure steam heating systems (the so? v called'vapor vacuum heating systems) for the purpose of venting air to the at-mosphererand prevent-ing entrance of the outer air into the line subsides below atmospheric pressure. Its

objects are to furnish a valve-of this'generalv character adaptedto perform the functions vabove referred torand havingin addition means, controlled by steam which may enter the return line under certain circumstances,

,for substantially preventing escapeof steam through the vent whenthe pressure yin the return line is higher than atmospheric, and for positively opening theY vent when Vthe return linepressure at the time of entrance.

of the steam is below atmospheric pressure, in order to break the vacuum. To this extent the objects are essentially the same asthose of the valve disclosed inthe application ofl `Charles W. Stewart filed October 9, 1930,

Serial No. 487,440; but my invention has the further objects of causing `both of the steam controlled JJunctions of the valve to be effected by the heat of the steam entering the return line, and also of devising improvements inV the constructionof the valve as an article of manufacture and commerce. This valve is adapted to be used in conjunctionwith a crossl overdevice, which permits steam from the boiler to pass into the return line when the pressure dierential exceeds ja"certain prescribedY maximum; di'li'erential` as used in this speciiication means the excess of the boiler pressure over the pressure in the return line of ,the'systemm A type of cross over,l device usable for this purpose and preferable to others, isadifferential loop of the character ,shown and de:

scribed in the patent of George D."Hoiiman,

No. 1,572,482, February 9, 1926. Preferably such loop and the valve of my invention are connected with the dry return line atV the high point of such line in accordancewith the principles explained in the patento'f yRalph Ray Emerson, N o. 1,639,084,August16, 1927,

alhough the protection whichl claimiS not uum therein.

The term pressure-fV limitediin its broadest aspects to such association.

' The vpreferred embodiment of the invention land preferred"association: with theheating `system are described in the following spec-V l ification and shown in the drawing, in Vwhich Fig 1 is an elevation of the boiler and the .Fig.'2 is a sectional view ofthe valve and the immediately adjacent pipe connections, showing the interior parts of the valvein` their position of equilibrium at atmospheric pressure and temperature; 5

Fig. 3 isa similar view showingthe working parts of the valve in the position assumed when. live steam lflows into the return line and the pressure therein,v is higher than the .atmospheric pressure; y l l Fig. 4is a similar view showingthe position taken by the parts when steam has entered the steam line in consequenceof'a vac- Like reference characters designate the lsame parts wherever they occur in all thev figures.

10 represents aboiler adapted to furnish Lsteam at low pressure for heating purposes,

and typiies anyboiler suitablefor the purpose.` 1 1 is vthe boiler-coupled end of the steam main or pipe by which `boiler steam isconductedto the heating radiators. 12l isl Vthe high endof the dry return line-which makes a circuit of the building in parallel with the. steam main, and is coupled-with return outlets'otthe radiators, finally l]o1`n1ng the wet return line 13 which leads back to the. boiler. 14 is a differential ,loop such as that shown in the before named H011'- mangpatent, connected with the steam space fof theboiler through a pipe 15 and having an overflow drip connection back to the boiler through a. pipe 16. It typities any cross over devicel of the character previously mentioned. ItsVV blow over Steam space is connected by a'pipe 17 with the dry return line, 12. This Combination is essentially like that described in the above named Emerson patent and has the same functions and results. That is, whenever the pressure differential exceeds a given maximum, for which the differential loop is designed or set, enough steam is allowed to pass into the return line to balance such excess and restore the prescribed differ-Y` ential. Such excess may occur either by generating` too high pressure in the boiler vabove the atmosphere, or by creating a sudden vacuum in the return line without reduction of the boilerpressure. The operation of the loop prevents generation of high enough unbalanced pressure in the boiler vto force water to a danverous extentl out ofv the boiler into the returnli'ne.

My improved vent valve is shown at 18, conveniently mounted in a pipe T 19, in the lateral branch of such T, which is located atl the upper side, while the ends vof the T are secured respectively to the" return line 12 at one side and to a nipple of coupling pipe 2O at the other side which joins the steam pipe yfrom the blow over device. The

yvalve itself, in its 'preferred construction here shown, consists vof a base 21, of hexagonal external outlineso that it can he engaged by a wrench, and with an externallythreaded extension 22 adapted to be screwed into the pipe T, or any other suitable pipe fitting or casi-ng. On the opposite end from the exteiision22 are externally threaded shoulders 23 and 24, of which the last named is of smaller diameter than the first named one. The`4 base. is hollow internally, having aV relatively large chamber 25, in the extension 22, which is bounded by a shoulder 26and having'in the opposite end a bore 27, communicating with chamber 25, and of which the outer rim is beveled toV provide a valve seat 28. A check valve 29 is fitted to said seat and isarranged to be closed bygravity, and' to be pressed upon toward the 'seat by the external atmospheric pressure. It is freeto move `'away from its seat and light in weight so that' it: may ope-n and ypermit release of air from the return line at alpressure very' slightly above the atmospheric pressure. A pressure excess of about l of an ounce per square yinch is sutlicient thus to open this check valve element in the commercial valve.

' ment'is equipped with guiding prongs 30 on ,cylindrical boxes or drums having flexible'k vvits under side and a cup 31 on its upper side,

to keep it Afrom falling entirely out of-place 4 in shipment and handlingof the valve'before installation. Y

A thermostat 32 is connected to the'base 21`so1as-t'o protrude therefrom into theffitting or casing to which thebase is applied. This thermostat is vpreferably ofthe drum type, consisting of a series of wide shallow diaphragmsas their end walls and centrally connected to one another with intercommuni-` cation, and containing volatile liquid. The

Said eledrum at one end of the series is connected to a supporting frame 33, made conveniently of a. U-shaped strip of stiff sheet kmetal, to the cross member of which the thermostat'issecure'd by a stem 34 passingfrom its endmost drum, and a nut35- screwed' on the protruding end of the stem. A dish or cross bar 36 is lacedbetweenthe.lees. of the frame strip, above the thermostat and is provided withv lugs 37V at opposite points, which pass into holes inthese legs whereby the disk is retained in place.v The circumference of the disk, or shoulders of an equivalent cross bar besiderthe lugs 37, engage the inner sides of the legs of the frame piece and hold such legs apart. These legs'V exte-ridbeyond the cross piece andare free to be sprung toward one another. Their spacing is such that theirl outermost points are slightly. wider apart than the internal diameter of chamber 25,`

whereby they may bepassedlinto the chamber when 'slio'htl 1 s )run-0" inward but not T7 Y C 7 otherwise. rlhus j when insertedV theyv exert outward pressure on the walls of the chainber, causing friction which is adequate -to f tral hole in the cross bar V36 whereby itis guided toward the valve element 29,l termi-j nating so near the latter that the thermostat, when expanded by the heat of live stream,

will unseat the valve, but when contracted by a temperature slightly' belowi212o F., the, vtemperature ofA steam at atmospheric pressure, will leave the valve seatec.

y A supportin the nature of an inverted cup 39vhavingv an internal thread'at its rim and holes in its side walls, isscrewedY on the shoulder 24. A thermostat 40, similar to thermof stat 32, Yis mounted 4on the end 'wallie of this cup, by means of a stem andrnut like those at Y 34 and 35. rhe uppermost wall of thermostat 40 carriers a valve element. 41. -A cover shell 42 is screwed on the shoulder 23 and encloses thermostat 40 and valve member 41. It has an internal lip 43 concentric and adjacent to the valve element 4l and providing a seat against which the valve may close when the thermostat 40 is expanded by the heat of llive steam, but from which the valve is withdrawnzwhen thethermostat is contracted by cooliiigto temperatures below212O F. rlhis shell vis tightly joined tothe base so as to prevent leakage of steam, and has a dome 'extension 44l at its upper end, protecting the valve element 41 and valve seat43, inthe sides of which extension are outlet openings 45.

ormally the valve eleinents'and' thermol' stats occupy positions as shown in Fig. 2.

"Then the check valvev element is free to be opened by air in the return line at a slight excess of pressure overvthe atmosphere, and valve element 41 is continually open to permit escape of such air. But the check valve is free to seat by gravity and by excess of external atmospheric pressure to vprevent entrance of air to the return Vline when the system is operated under vacuum,- as it frequently is Aduring mild weather when low temperature vapor is sufficient to furnish all the heat required. The ability of the so called vapor vacuum heating systems to furnish heat'from boiler` water at a temperature below 212 F. is dependent on' the ability to "maintain a vacuum in the return line and radiators, which in turn is secured by the check valve 29, since the port 27, which this valve controls, is the only opening through which air is vented from the system and at which flow of air into the system must be prevented in order to obtaina vacuum.

Occasions arise more or less frequently, however, when steam is admitted directly into the return line by the cross over device. If such an occasion is due to rise of the boiler pressure above the prescribed differential (which in many heating systems is limited to 10 ounces per square inch) ,it is important that the valve be tightly closed quickly in order not only to avoid loss of steam but, which is more important, to confine the pressure of the steam in the return line and cause 'it to Y Y `the return lme vacuum, a large volume ofcompress the air already in the line to a degree high enough to balance the excess of boiler pressure over the differential and prevent water backing from the boiler into the return line. But if the excess differential occurs by sudden vacuum in the return line without a corresponding decrease of boiler` pressure, it is important to open the vacuum check so as to admit air quickly and thus not only shorten the time and diminish the volume of steam necessary to build up the return line pressure, but also prevent the noise re- I sulting from flowl of steaminto areturn line 'which is under vacuum. Bot-hof these conl ditions are efficiently met by'this valve.

When steam passes the Vcross over device with the return line at atmospheric pressure, it passes the check valve element, of course, but immediately encounters the thermostat 40 and expands it to close valve element 41 very quickly and before any considerable amount of steam has escaped. It then'cornpresses the air in the return line to a degree lby 10 ounces, or whateverpother value which is less than the actual boiler pressure may be fixed as the pressure'. differential. Only a comparatively small amount of steam is required for this, usually not over 5% of the total returnline volume, when the cross over device is connected to the high point of the return line.

boiler pressure will be due to the reduction in demand for steam.-

broken, to fill the return line with steamv so 'as to prevent backing of water from the boiler. When steam lthus fills the line, it causes clickingvor chattering of the outlet traps of the radiators, due to opening of the traps for release Vof condensation and the attempt of steam in the return line to flow into the'radiator counter to the outflow of water which is trying to pass fromr the radiator into the return line. This condition can be obtained only when the pressure in the return is greater than that in the radiator, but such occasions'occur rather frequently. For example, when radiatorsl in the bed rooms of dwellings are turned off at night and the windows are opened, vacuum will quickly develop yin such radiatorsand, when the condensate-release r.traps of the radiators open, the air previously existing in the return line, the volume of which is small as'compared with the volume of the radiators, will expand" into the shut Voff radiators, leaving but little air in the return line and causing a relatively high vacuum therein. At the. same time the somewhat increased The consequent increased pressure differential causes action of the cross over'device,

passing boiler steam into the return line.

In'the absence of means for then breaking steam -would thus pass,causing the objectionable noise above mentioned. The thermostat 32'of my valve constitutes means for breaking the vacuum in such circumstances. Being in the return line and directly in the path ofentering steam, it is instantly affected by the heat of such steam and quickly expands, forcing the check valve element frorngits seatV against theV atmospheric pressure, and allowing air to yenter the return line, as shown by" Fig. 4. In order to intensify and hasten this action, the T fitting 19 is made with an internal partition 461 at the steam inlet end, in `which there is a relatively small orifice 47 arranged to restrict the steam flow anddirect a jet of steam directly on the thermostat, so that the action of the latter occurs beforeV any considerable amount of steam has passed, that is, before enough steam has entered to expand the thermostat 40 and close l contracts, being then surrounded by cool air,

vand the check valve is allowed to close, to

lIt the action above described has occurred vvhen the boiler pressure is below atmospheric, or only slightly above it, such closing of the check valve is necessary to maintain a differential requisite for circulation of steam through radiators which have not been shut otf.

eturning to the structural detail of the valve, it will be noted that the cup 3l on the check valve element 29 projects toward the end wall of the supporting cup 39 and receives the protruding end of the stem by which thermostat 40 is secured to said wall. These parts, while they do not interfere at all with the functioning of the check as described, do cooperate with one another and with the guide fingers 30, in .preventing the check from falling out ofy place when the valve is tipped on its side or turned upside Adown in handling, and they cause the check to drop correctly into place when the valve is set upright.

While the details of construction and arrangement here described are practically important 'from the viewpoint of efliciency and cost of manufacture, and efficiency of'operation, of a commercial valve, and are therefore claimed as a valuable phase of the invention, nevertheless the broader aspects of the invention vare not limited to these details and. various modifications of the parts and their association, and substitution of equivalents for the specific elements here shown, are

contemplated within the scope of the protection claimed.

l/Vhat I claim and desire toV secure by Letters Patent is:

l. A valve of the character and for the purpose set forth, comprising a base having a passage and a valve seat, a checl valve element A cpmplemental`to said seat for closing vand opening said passage, a thermostat connected to one side of the body and having means for unseating the valve element when affected by high temperature, a second thermostat and connected valve element mounted on said body at the outlet side thereof, acasvalve element and second thermostat and having an outlet con- +11olled by the second valve element.

"2. A valve of the character described com- 1 prising a casing having inlet'and outlet openings, a thermostatically controlled valve for said outlet arranged to be closed under lhigh temperature 'conditions and opened under low temperature conditions, a check valve for said inl-et., and a thermostat external to the casing and disconnected from said check valve brit arranged to unseat the same when affected by high temperature conditions only.

3. A valve comprising a base having a throughpassage, a casing enclosing said passage in hermetic connection with the base and having an outlet orifice, a check valve cooperating with the passage in the base and arranged toopen inwardly with respect to the casing, a thermostat connectedy to the base and having means for unseating said check valveV when inii'uencedby high temperature, but otherwise leaving the check valve free to be opened and closed by pressurey diiierences,

and a thermostatic valve for said outlet organized to close the same when heated above a given temperature and to open 1t when i cooled below said temperature.

4. A valve for the purpose described comprising a base having an internal chamber at one side, la passage leading from said chamber to the other side, and a valve seat surrounding said passage, a check valve cooperating with said seat, a thermostat holder secured in said chamber and projecting outward-therefrom, a thermostat mounted on said holderadapted to be expanded by rising, and contracted-Y by diminishing, temperatures, a stem between the thermostat'` and check valve arranged to transmit motion for opening the valve from the expanding thermostat, a casing secured hermetically to said base enclosing said passage, valve seat and check valve and having an outlet orice, a thermostat within said casing anchored to the Y baseV adapted to be expanded by heating and contracted by cooling, and a valve c-arriedzbyV said thermostat in cooperation with saidoutl-et arranged to close the latter when the thermostat is expanded by heat of Y.a ,predetermined degree. Y

5. A vacuum check valve for connection in the return line of a steam heating system,

preventing inflow of outside air to the casing,

adaptedto be opened for escape of air within the casing at a pressure slightly higher than atmospheric pressure, a thermostat adapted,

when aiiected byheat, to open the communication between the interior of the casing and the outer air, and a second thermostat adapted, when affected by heat to close the communication'between the interior of the casing and the outer air.

7. A valve of the character described comprising ya casing having a vent outlet with a plurality of valve seats in series, a check valve` Cooperating with one of said seats to prevent inflow of air to the casing and adapted to be opened by slight excess of pressure Within the casing to permit escape of air therefrom, a thermostatic valve cooperating With the other of said seats adapted to be closed when affected by high temperature and opened When affected by a lower temperature, and a thermostat in position to be affected by the heat of steam entering the casing and arranged to open said check valve when so affected.

8. A valve comprising a c-asing adapted to be connected in the return line of a steam heating system having an entrance and an exit for steam and air flowing through such line, and having an intermediate opening to the outer air, a check Valve over said opening adapted to be closed by excess of outside pressure and to be opened by, a slight excess of pressure Within the casing, and a thermostat adapted to open said check valve when eX- pandedby heat; the inlet opening of the casing being of restricted area and being located Where steam passing through it into vthe casing is caused to blow directly on said thermostat. f

In testimony whereof I haveaiiixed my signature.

WILLIAM K. SIMPSON. 

